The dead man in Yossarian's tent was a pest, and Yossarian didn't like him, even though he had never seen him. Having him lying around all day annoyed Yossarian so much that he had gone to the orderly room several times to complain to Sergeant Towser, who refused to admit that the dead man even existed, which, of course, he no longer did.
-- Catch-22 by Joseph Heller
There are some things that don't exist that annoy me. Affordable personal rocket packs for one, mainly for the very reason that they don't exist... yet.